I had the same problem with my last hatch. At the end of day 18 when I took them off the turner there were 20 eggs with movement (however not all of them seemed to be as developed as the rest) but only 10 hatched. The other 10 did nothing. It is very dissapointing but I have no clue what happened. My first hatch went great 20 out of 24 eggs. I don't know if anyone ever really knows what happens when everything seemed to be perfect during incubation. Good luck! Maybe they are just a little late.

Accurite or Springfield Thermometer/Hygrometers can be purchased at Wal-marts..some use more expensive ones like a Flukers....they read your inside temps and humidity and are placed inside the bator...